JPH02235941A - Preparation of work piece made of fiber-renforced composite material - Google Patents

Abstract

PURPOSE: To perform treatment with high safety and good reproducibility by using an aq. soln. of peroxodisulfate in subjecting works made of a fiber composite material to preparatory treatment before subjecting the same to wet chemical treatment such as adhesion.

CONSTITUTION: Works made of a fiber composite material are preparatorily treated with an aq. soln. containing peroxodisulfate ions, pref., an aq. soln. containing 75 g/l of ammonium peroxodisulfate [(NH₄)₂S₂O₈] before subjected to wet chemical treatment, especially, adhesion to be increased in adhesive strength thereof.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for preparing workpieces made of fiber composite materials, in particular before bonding, the surface area of which is subjected to a wet chemical treatment. [Prior Art] When pretreating workpieces made of fiber composite materials to be bonded together by adhesive, mechanical grinding processing methods are mainly used today; In order to guarantee the necessary reproducibility of the surface quality of the workpieces to be joined, which only guarantees optimal adhesion of the bond, relatively high monitoring costs are required. On the other hand, during such mechanical pretreatment it cannot necessarily be assumed that the strength properties of the thus pretreated workpiece are intact. Another possibility for obtaining a reproducible, residue-free surface, such as that required for bonding, is that in some cases, the strip-off fabric still present from the manufacture of the fiber composite workpiece is removed immediately before bonding. is obtained by first removing . However, this method cannot be used in many areas, and therefore the reliability of this method is limited to all expected (+
) The combination of fiber composite materials and adhesives must be newly proven. Particularly in fiber composite materials with improved strength properties, this method often also produces quite unsatisfactory results. Finally, as mentioned at the beginning? Attempts have already been made to use the III type chemical pretreatment method. However, these methods have traditionally been relatively ineffective, or their introduction into raw materials processes has conflicting occupational health perspectives, as in the case of the use of chromium sulfate for this purpose. are doing. [Problem to be Solved by the Invention] The problem of the invention is to develop a method of the kind mentioned at the outset without requiring substances whose large-scale use appears to be dangerous for occupational health reasons. , to develop a reproducible pretreatment of the surfaces of workpieces made of fiber composite materials, which is possible with chemical methods. [Means for Solving the Problem] The present invention solves this problem by a method in which the wet chemical pretreatment is carried out using an aqueous solution containing a peroxodisulfate (32O8) ionic component. In this case, it is preferred to use an aqueous solution of ammonium peroxodisulfate ((NH4)2 52OB), preferably at a concentration of about 75 g/II in a preferred embodiment of the process according to the invention. Due to this reactive modification of the workpiece surfaces to be bonded, the components produced by gluing achieve excellent strength properties, the bond being at the same time extremely resistant to climatic influences, in particular high temperature and humidity. There is. This means that the surface is coated with a commercially available adhesive (Hysol EA9
321) in various ways before adhesion by mechanical or Il
Lii! Simply stacked shear tension specimens consisting of carbon fiber reinforced components that were chemically pretreated and exposed to humid conditions (70°C water) until the bonded specimens were saturated. This can also be confirmed by mechanical testing of experimental samples. 7. Comprising ammonium peroxodisulfate.
The samples pretreated with oxidation using a 5% aqueous solution not only showed the highest strength values in the tensile test of all the samples examined, but rather the fracture surface morphology showed that the highest strength of adhesive failure was observed in these samples. It turned out that there was a percentage. These results apply both to the unexposed condition and to the unexposed condition under the given high temperature and humidity conditions. The high rate of bond failure under precisely these conditions shows that the joint surfaces can be rendered sufficiently climatically insensitive by wet chemical pretreatment according to the method of the invention. Pretreatment of the joint surfaces can be carried out by immersing the workpiece in a solution, or by spraying the workpiece with a solution or by applying a thixotropic thixotropic paste containing peroxodisulfate ions. This can be done by Subsequently, the workpiece must be thoroughly cleaned and dried. In conclusion, it can be said that the method according to the invention is also suitable for the pretreatment of workpieces made of fiber composite materials, which subsequently have to be provided with a coating, for example as a surface protection. Haftung

Claims (1)

Claims: 1. A method of preparing a workpiece made of a fiber composite material, the surface area of which is subjected to a wet chemical treatment, wherein the treatment is carried out using an aqueous solution containing a peroxodisulfate (S_2O_8) ionic component. A method for preparing a workpiece made of fiber composite material, characterized in that: 2. Process according to claim 1, characterized in that the solution contains ammonium peroxodisulfate ((KH_4)_2S_2O_8). 3 The ammonium peroxodisulfate component in the solution is about 7
3. Process according to claim 2, characterized in that it is 5 g/l.